Ctrl-a is a hotkey as well. It is Unix code, which MacOS uses, for "PgUp", scrolling the browser window up so I can only see the top half of the gamescreen. It's just in general a good idea to steer away from using "ctrl" as a key in a web-based game or any game, really. Too many possibilities of overlap with pre-existing hot-keys. Just a little advice for the future.